1. Field of the Invention
This invention relates to an information display apparatus provided with a light emitting display plate of the panel type wherein internally generated light is radiated to both of the front and rear face sides as well as a display state detection method for detecting a display state of the information display apparatus, a display state adjustment method for adjusting the display state of the information display apparatus, and a maintenance management method for the information display apparatus.
2. Description of the Related Art
Conventionally, for video display apparatus such as television receivers and computer display units, an apparatus such as a CRT (cathode ray tube) or an LCD (liquid crystal display device) is used popularly. In recent years, also a display device of the panel type which by itself emits light in response to application of voltage thereto such as plasma display panel (PDP) has been put into practical use. Since those display devices have a tendency that the display state such as a luminance (brightness) or color temperature is gradually varied by aged deterioration or the like as a result of use for a long time, adjustment must be performed occasionally in order to keep the display state in the best.
Conventionally, adjustment of a screen display state such as a brightness or color temperature of such a display apparatus as described above is performed periodically or as occasion calls by a maintenance engineer or a user. For such adjustment, two methods are popularly used including a method wherein optical sensors are suitably arranged at suitable positions of the display face side (observer side) and output signals from the sensors are received by an adjustment apparatus for exclusive use to directly detect a display image and then adjustment is performed suitably so that an appropriate display image may be obtained and another method wherein a display state is detected indirectly by detecting current, voltage or a like parameter which participates in the display to effect adjustment.
However, while the former one of the two methods described above is advantageous in that it allows adjustment with a high degree of accuracy because an image displayed actually is monitored directly, it is disadvantageous in that, since the optical sensors are arranged on the display face side, part of the display information is intercepted by the optical sensors. Particularly in an application wherein complete information display is always required to a user such as, for example, a guide display unit in a public equipment such as the yard of a station or the departure and arrival terminal of an airport or in a shopping center such as a department store, any method by which part of display information is intercepted even for a while cannot be adopted. Further, with the former method described above, since installation of an adjustment apparatus for exclusive use is required in addition to installation of the optical sensors upon adjustment, much time is required for preparations prior to the adjustment. Accordingly, in such an equipment as mentioned above wherein a very large number of guide display units are provided, it is almost impossible for all of them to be always managed appropriately by a maintenance engineer or engineers, and it is difficult to rapidly find out a display unit which has failed or has suffered from deterioration in picture quality and take a countermeasure against such failure or picture quality deterioration.
On the other hand, the latter method is realized, where, for example, a CRT display unit is taken as an example, in such a form that current flowing through an electron gun is supervised to detect a display state of the tube screen (fluorescent screen). With the method, however, the display state is merely monitored indirectly from current which participates in the display, and if the current and the display state are brought out of a correct corresponding relationship by some factor such as, for example, degradation of the fluorescent substance or leak of current, then the accuracy in detection of the display state, and hence the accuracy in adjustment, is degraded significantly.
In this manner, in a conventional video display apparatus, it is difficult to normally keep a good display state or discover a failure rapidly, and if it is tried to overcome the problem just described using any of the conventional methods, a high cost and much time are required and it cannot be avoided that some obstacle to the business or to the service to a user occurs.
It is an object of the present invention to provide a display state detection method which allows the display state to be supervised accurately and allows a countermeasure to be taken rapidly without giving any obstacle to a user. It is another object of the present invention to provide a display state adjustment method and a maintenance management method by which a display condition can be kept good without giving any obstacle to a user. It is a further object of the present invention to provide an information display apparatus to which the methods are applied.
In order to attain the objects described above, according to an aspect of the present invention, there is provided an information display apparatus, comprising a light emitting display plate having a shape of a flat plate for generating light in the inside thereof in response to information given thereto and radiating the internally generated light to both of the front and rear face sides, and display state detecting light detection means provided on the rear face side different from a display face of the light emitting display plate.
The information display apparatus may further comprise automatic adjustment means for automatically adjusting the display state of the light emitting display plate based on display state detection information obtained by the light detection means. Preferably, the automatic adjustment means outputs an alarm when the adjustment thereby has failed. Here, the information display apparatus may further comprise maintenance management information holding means for holding apparatus maintenance management information including a history of adjustment performed by the automatic adjustment means. In this instance, the information display apparatus may further comprise outputting means for outputting the apparatus maintenance management information held by the maintenance management information holding means or the display state detection information outputted from the light detection means to the outside. The outputting means may be connected to a central control unit provided for controlling and managing a plurality of information display apparatus of a similar type.
In the information display apparatus, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected. Further, the display state of the light emitting display plate is automatically adjusted based on a result of the detection. Besides, the apparatus maintenance management information including an adjustment history is held. Furthermore, the apparatus maintenance management information or the display state detection information is outputted to the external central control apparatus or the like.
With the information display apparatus described above, since the light detection means is provided on the rear face side of the light emitting display plate such that, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated toward the rear face side which is not the display face may be detected, upon ordinary information display, the information display apparatus is advantageous in that the presence of the light detection means does not make an obstacle at all when the display screen is observed. Besides, since an operation to dispose an optical sensor and connect it to an adjustment apparatus for exclusive use each time adjustment is to be performed is not required, the information display apparatus is advantageous also in that supervision of the display state is facilitated very much and the cost required for the supervision can be reduced remarkably. Further, since, different from a method wherein the display state is detected indirectly from current or a like parameter which participates in the display, the display state of the light emitting display plate is detected directly by the light detection means, the information display apparatus is advantageous further in that detection with a high degree of accuracy is possible.
Where the display state of the light emitting display plate is automatically adjusted based on a result of the detection by the light detection means, the information display apparatus is advantageous in that the display state can be kept optimum without requiring manual operation as in the prior art. Further, where the apparatus maintenance management information including an adjustment history is held, the information display apparatus is advantageous in that it is possible to grasp the condition of use or the deterioration condition of the apparatus or effect prediction of the life of the apparatus and so forth precisely based on the information. Particularly where the apparatus maintenance management information or display state detection information is outputted to the outside, it is possible to effect grasping of the condition of the apparatus and so forth from the outside.
According to another aspect of the present invention, there is provided a display state detection method for an information display apparatus comprising the steps of providing light detection means on the rear face side different from a display face of the light emitting display plate, and detecting a display state of the light emitting display plate based on an output of the light detection means.
In the display state detection method for an information display apparatus, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected.
With the display state detection method for an information display apparatus, since, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected by the light detection means provided on the rear face side of the light emitting display plate, the display state detection method is advantageous in that the presence of the light detection means does not make an obstacle at all when the display screen is observed, and besides, supervision of the display state is facilitated very much and detection of the display state with a high degree of accuracy is possible.
According to a further aspect of the present invention, there is provided a display state adjustment method for an information display apparatus, comprising the steps of providing light detection means on the rear face side different from a display face of the light emitting display plate, detecting a display state of the light emitting display plate based on an output of the light detection means, and automatically adjusting the display state of the light emitting display plate adjusted based on a result of the detection by the light detection means.
In the display state adjustment method for an information display apparatus, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected, and the display state of the light emitting display plate is automatically adjusted based on a result of the detection.
With the display state adjustment method for an information display apparatus, since, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected by the light detection means provided on the rear face side of the light emitting display plate and the display state of the light emitting display plate is automatically adjusted based on a result of the detection, the display state adjustment method is advantageous in that the display state can be kept optimum without requiring manual operation as in the prior art.
According to a still further aspect of the present invention, there is provided a maintenance management method for an information display apparatus, comprising the steps of providing light detection means on the rear face side different from a display face of the light emitting display plate, detecting a display state of the light emitting display plate based on an output of the light detection means, automatically adjusting the display state of the light emitting display plate adjusted based on a result of the detection by the light detection means and holding apparatus maintenance management information including a history of the automatic adjustment, and performing maintenance management of the information display apparatus suitably referring to the apparatus maintenance management information.
The maintenance management method for an information display apparatus may further comprise the step of sending out the apparatus maintenance management information held by the maintenance management information holding means or the display state detection information outputted from the light detection means to a central control unit provided for controlling and managing a plurality of information display apparatus of a similar type so that the maintenance management of the information display apparatus may be performed by the central control unit.
In the maintenance management method for an image display apparatus, the held apparatus measurement management information including an adjustment history is suitably referred to to effect maintenance management of the information display apparatus. Further, the apparatus maintenance management information or the display state detection information is sent out to the central control apparatus, and maintenance management of the information display apparatus is performed by the central control apparatus.
With the maintenance management method for an image display apparatus, since, of the light radiated to both of the front and rear face sides of the light emitting display plate, the light radiated to the rear face side which is not the display face is detected by the light detection means provided on the rear face side of the light emitting display plate and the display state of the light emitting display plate is automatically adjusted based on a result of the detection and besides the apparatus maintenance management information including a history of the adjustment is held, the maintenance management method is advantageous in that maintenance management of the apparatus can be performed precisely based on the information such that a condition of use or a degradation condition of the apparatus is grasped or prediction of the life of the apparatus and so forth can be performed. Particularly where the apparatus maintenance management information or the display state detection information is sent out to the central control apparatus and maintenance management of the information display apparatus is performed by the central control apparatus, display states and so forth of a large number of information display apparatus can be managed in a concentrated manner from a remote place.